piano scale
D♯ Lydian
D♯1E♯2F𝄪3G𝄪♯4A♯5B♯6C𝄪7
Major with a raised fourth. The fourth mode of the major scale.
The same sounds spelled from the other side are E♭ Lydian.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
D♯WE♯WF𝄪WG𝄪HA♯WB♯WC𝄪HD♯
What is true of it
D♯ Lydian is D♯, E♯, F𝄪, G𝄪, A♯, B♯ and C𝄪, and back to D♯.
Its steps are W – W – W – H – W – W – H, where W is a whole step and H a half.
Written correctly it needs 10 alterations, F𝄪, G𝄪 and C𝄪 among them. That is what the letters force, and it is also why nobody writes music in this key: the same notes spelled from the other side are easier to read.
On the same tonic, D♯ major differs from it by exactly one note.
Chords made only of these notes
Found by testing every chord in the catalogue against these 7 sounds, not chosen.